1. Field of the Invention
The invention pertains to guides for roller chain producing tensioning of the chain by lateral chain displacement.
2. Description of the Related Art
Chain guides such as those used to maintain the tension within the roller timing chain systems in internal combustion engines laterally displace the chain "inwardly" intermediate sprockets to maintain a predetermined tension on the chain in order to insure proper timing of the cylinder ignition sequences.
For many years, internal combustion engine timing chain guides have utilized synthetic material defining the wear surface which engages the chain, as shown in U.S. Pat. Nos. 2,963,918, 3,407,674, 4,921,472, 5,266,066, 5,462,493, and the like. As will be appreciated from these patents, self-lubricating synthetic plastic material, such as nylon, is commonly used to define the wear surface engaging the roller chain.
While such prior art devices are commonly used, the wear surface, and adjacent body, is usually formed of an unreinforced nylon or similar polymer, and even though such material is self-lubricating, wear occurs and periodic replacement of the chain guide is required.
It would be possible to reinforce the nylon with a fiberglass reinforcement utilizing glass fiber strands. However, such a reinforcement of the nylon would be unacceptable as it would produce an increased wear on the chain, and the glass fibers would separate from the guide material in minute amounts and contaminate engine lubricants and destroy critical wear surfaces.
Previously, a long wearing chain guide has heretofore not been available for internal combustion engine timing chain systems.